Washing machine and method for controlling spin-drying thereof

ABSTRACT

Disclosed are a washing machine having a drying device, which performs a spin-drying operation at a maximally low RPM and supplies cold air to clothes in a delicate course so as to minimize damage to the clothes and improve rinsing and spin-drying efficiencies, and a method for controlling spin-drying of the washing machine. The method for controlling spin-drying of the washing machine, which has a rotary drum for containing clothes, a motor for rotating the rotary drum, and a fan for circulating air into the rotary drum, includes determining whether or not a delicate course is selected; performing low-speed spin-drying in which the rotary drum is rotated at a low speed by operating the motor at a low RPM, when it is determined that the delicate course is selected; and supplying cold air to the inside of the rotary drum by operating the fan together with the low-speed spin-drying.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Korean Patent Application No. 2007-0021487, filed Mar. 5, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments relate to a washing machine having a drying device, and more particularly, to a washing machine, which increases a spin-drying effect while minimizing damage to laundry such as clothes, and a method for controlling spin-drying thereof.

2. Description of the Related Art

Generally, drying devices are devices, which dry wet laundry (such as clothes) by supplying hot air heated by a heater to the inside of a drum containing the laundry while rotating the drum at a low speed. Recently, a washing and drying machine (usually, a drum washing machine) having such a drying device has come onto the market, and performs a drying operation independently or after spin-drying in connection with a washing operation.

In order to minimize damage to clothes made of a fabric requiring delicate washing, such as wool and silk, the above washing machine having the drying device performs a delicate course, in which a middle spin-drying operation after washing and rinsing operations is skipped or the spin-drying operation is carried out at a low revolutions per minute (RPM). Further, in the delicate course, a final spin-drying operation is restrictively applied, thus minimizing damage to the clothes.

Since the middle spin-drying operation after the washing and rinsing operations is skipped or the spin-drying operation is carried out at a low RPM, the above delicate course minimizes damage to the clothes. However, the delicate course is disadvantageous in that the rinsing of the clothes is poor. Further, in order to minimize damage to the clothes, the final spin-drying operation is restrictively applied, and thus a final spin-drying degree is low and a spin-drying efficiency is deteriorated.

In order to solve the above problem, Japanese Patent Laid-open Publication No. 2005-334346 proposes a method for supplying hot air to improve a spin-drying degree in a final-spin drying operation. This method improves a spin-drying efficiency through hot air supply using a drying device, but cannot be used in clothes, which are damaged by heat. Further, this method is accompanied by energy consumption due to heat.

SUMMARY

In accordance with one aspect, there is provided a washing machine having a drying device, which performs a spin-drying operation at a maximally low RPM and supplies cold air in a delicate course so as to minimize damage to clothes and improve rinsing and spin-drying efficiencies, and a method for controlling spin-drying of the washing machine.

In accordance with one aspect, there is provided a method for controlling spin-drying of a washing machine, which has a rotary drum for containing laundry, a motor for rotating the rotary drum, and a fan for circulating air, including determining whether a delicate course is selected; performing low-speed spin-drying in which the rotary drum is rotated at a low speed by operating the motor at a low revolutions per minute (RPM), when the delicate course is selected; and supplying cold air to the inside of the rotary drum by operating the fan together with the low-speed spin-drying.

The low RPM of the motor may be at least 250 RPM.

The low RPM of the motor may be in the range of 250˜400 RPM.

The low-speed spin-drying may be performed such that the motor is operated at the low RPM in a middle spin-drying operation after a washing operation.

The low-speed spin-drying may be performed such that the motor is operated at the low RPM in a final spin-drying operation.

The cold air may be supplied to the inside of the rotary drum such that the fan is operated during operation of the motor at the low RPM so as to supply the cold air generated from the fan to the inside of the rotary drum rotating at the low speed.

In accordance with another aspect, there is provided a washing machine including a rotary drum to contain laundry; a motor to rotate the rotary drum; a fan to circulate air; and a control unit to control spin-drying in a delicate course by operating the motor at a low revolutions per minute (RPM) so as to perform low-speed spin-drying in which the rotary drum is rotated at a low speed, and to operate the fan together with the low-speed spin-drying so as to supply cold air to the inside of the rotary drum.

The control unit may control the motor such that the low-speed spin-drying is performed in a middle spin-drying operation after a washing operation.

The control unit may control the motor such that the low-speed spin-drying is performed in a final spin-drying operation.

The low RPM of the motor may be at least 250 RPM.

The low RPM of the motor may be in the range of 250˜400 RPM.

The washing machine may further comprise a duct for guiding the route of the air circulated by the fan, and the fan may be installed in the duct.

The washing machine may perform washing and rinsing operations, and may skip a middle spin-drying operation after washing and rinsing operations are completed to perform the low-speed spin drying.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects, features, and advantages will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a sectional view of a washing machine having a drying device in accordance with an exemplary embodiment;

FIG. 2 is a block diagram of a control system of the washing machine having the drying device in accordance with an exemplary embodiment; and

FIG. 3 is a flow chart illustrating a method for controlling spin-drying of the washing machine having the drying device in accordance with an exemplary embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Exemplary embodiments are described below to by referring to the figures.

FIG. 1 is a sectional view of a washing machine having a drying device in accordance with an exemplary embodiment.

As shown in FIG. 1, an exemplary embodiment of a washing machine includes a tub 11 having a drum shape installed in a main body 10 for containing water (washing water or rinsing water), and a rotary drum 12 rotatably installed in the tub 11 and provided with a plurality of dehydration holes.

A motor 13 for rotating the rotary drum 12 in a regular or opposite direction so as to perform washing, rinsing, and spin-drying operations is installed under the tub 11, and a washing heater 16 for heating the water (specifically, the washing water) supplied to the inside of the tub 11 when a user selects the temperature of the water is installed on the bottom of the tub 11.

An opening 14 is formed through the front surfaces of the tub 11 and the rotary drum 12 such that the user can put or take clothes into and out of the main body 10, and a door 15 for opening and closing the opening 14 is installed at the front surface of the main body 10.

A detergent supply device 18 for supplying a detergent, and a water supply device 20 for supplying water (the washing water and the rinsing water) are installed above the tub 11.

The inside of the detergent supply device 18 is divided into a plurality of spaces. The detergent supply device 18 is installed in the front portion of the main body 10 so that the user can easily put the detergent and a fabric softener into the respective spaces of the detergent supply device 18.

The water supply device 20 includes a water supply pipe 22 for supplying the water, and a water supply valve 24 installed in the water supply pipe 22 so as to control the water supply through the water supply pipe 22. The water supply pipe 22 is connected to the detergent supply device 18 so that the water from the outside is supplied to the detergent supply device 18. A separate connection pipe 26 is installed between the detergent supply device 18 and the tub 11 so as to supply the water, passed through the detergent supply device 18, together with the detergent to the tub 11, and a water supply nozzle 28 is installed at an outlet of the connection pipe 26. This structure allows the detergent in the detergent supply device 18, under the condition that the detergent is dissolved in the water, to be supplied to the tub 11.

Further, a drain device 30 for draining the water in the tub 11 is provided. The drain device 30 includes a drain pipe 31 connected to the lower portion of the tub 11 so as to guide the water in the tub 11 to the outside, and a drain pump 32 installed in the drain pipe 31.

Further, a drying device 40 for drying clothes (laundry) is provided.

The drying device 40 includes a fan 41 installed on the tub 11, a drying duct 42 connecting an outlet hole 41 b of the fan 41 and an air inflow hole 45 formed through the upper portion of the opening 14 of the tub 11, a condensation duct 43 disposed on the rear portion of the tub 11 so as to connect an air discharge hole 46 formed through the lower portion of the rear surface of the tub and an inlet hole 41 a of the fan 41, and a drying heater 44 installed in the drying duct 42 so as to generate air of a high temperature supplied to the inside of the rotary drum 12.

A spray nozzle 47, for spraying condensation water (cold water) into the condensation duct 43 so that water is condensed and thus is removed when air in a high-temperature and high-humidity state obtained by drying the clothes (laundry) passes through the condensation duct 43, is provided in the upper portion of the condensation duct 43. The spray nozzle 47 is connected to the water supply device 20 through a condensation water supply pipe 48 and a condensation water valve 49 so as to supply the condensation water.

Accordingly, the condensation water sprayed from the spray nozzle 47 flows down along the inner surface of the condensation duct 43, and thus increases contact with the ascending air in the high-temperature and high-humidity state, thereby improving a condensing effect.

Further, a discharge hole 43 a for discharging condensed water is formed through the lower portion of the condensation duct 43, and the condensed water discharged through the discharge hole 43 a flows into the drain pipe 31 of the drain device 30.

Hereinafter, the operation of the above washing machine having the drying device will be described.

When the washing machine is operated under the condition that clothes (laundry) to be washed are put into the rotary drum 12, the water supply valve 24 of the water supply device 20 is opened, and water (washing water) is supplied to the tub 11 through the water supply pipe 22 and the detergent supply device 18.

When the supply of the washing water is completed, the washing heater 16 is operated and thus heats the washing water contained in the tub 11 to a temperature required to wash the clothes. Then, the rotary drum 12 is rotated in a regular or opposite direction by the driving of the motor 13, and the clothes are washed by means of the friction with the rotary drum 12 and the decomposition power of the detergent.

After the washing of the clothes is completed, a rinsing operation, in which the supply of water and the drain of water are repeated, is carried out approximately 1˜5 times and a spin-drying operation, in which the rotary drum 12 is rotated, is carried out.

Thereafter, in order to dry the clothes (laundry), the drying heater 44 and the fan 41 are operated under the condition that the rotary drum 12 is slowly rotated by the driving of the motor 13. Then, the inhalation of the air in the rotary drum 12 to the fan 41 through the condensation duct 43 and the discharge of the air to the inside of the rotary drum 12 through the drying duct 42 are repeated.

Here, the air in the drying duct 42 is heated into a high-temperature and low-humidity state by the drying heater 44, and the air in the high-temperature and low-humidity state is supplied into the rotary drum 12. Then, the air in the high-temperature and low-humidity state (i.e., hot air) heats the clothes in the rotary drum 12, and thus evaporates moisture contained in the clothes, thereby drying the clothes.

In the above drying operation, the air in the high-temperature and low-humidity state absorbs moisture from the wet clothes and thus is converted into a high-temperature and high-humidity state, and the air in the high-temperature and high-humidity state is transferred to the condensation duct 43. Then, the air in the high-temperature and high-humidity state transferred to the condensation duct 43 contacts the condensation water (cold water) sprayed from the spray nozzle 47, and thus moisture in the air is condensed into water and the air is converted into a low-humidity state. The air in the low-humidity state is heated again by the drying heater 44 and then is supplied into the rotary drum 12. This process is repeated, and thus dries the clothes.

FIG. 2 is a block diagram of a control system of the washing machine having the drying device in accordance with an exemplary embodiment. In addition to the elements, as shown in FIG. 1, the washing machine in an exemplary embodiment further includes a signal input unit 100, a water level sensing unit 110, a temperature sensing unit 120, a drying sensing unit 130, a control unit 140, and a driving unit 150.

The signal input unit 100 allows a user to input operation data, such as a washing course (for example, a delicate course, a standard course, etc.), a washing temperature, a spin-drying RPM, the selection of the addition of rinsing, etc., which are selected according to the kind of clothes (laundry), to the control unit 140. Here, the delicate course can be applied to clothes requiring delicate washing, such as a wool or silk fabric, a shirt, a rayon fabric, and a women's top.

The water level sensing unit 110 senses the level of water supplied to the tub 11, the temperature sensing unit 120 senses the temperature of the water supplied to the tub 11, and the drying sensing unit 130 detects the temperature and humidity of the clothes (laundry) so as to sense the drying state of the clothes (laundry).

The control unit 140 is a microcomputer, which controls the washing machine based on the operation data inputted from the signal input unit 100. In the delicate course, the control unit 140 reduces the rotational frequency of the motor 13 to a low RPM (approximately 250˜400 RPM) in a middle spin-drying operation after a washing operation and in a final spin-drying operation after a final rinsing operation so that the rotary drum 12 is slowly rotated to achieve the spin-drying operation, and simultaneously operates the fan 41 so that cold air is supplied to the inside of the rotary drum 12.

The driving unit 150 serves to drive the motor 13, the washing heater 16, the water supply valve 24, the drain pump 32, the fan 41, the drying heater 44, the condensation water valve 49, etc. according to a driving control signal of the control unit 140.

Hereinafter, the operation of the above washing machine and the effect of a method for controlling spin-drying of the washing machine will be described.

FIG. 3 is a flow chart illustrating the method for controlling spin-drying of the washing machine having the drying device in accordance with an exemplary embodiment. A method of an exemplary embodiment relates to spin-drying of the washing machine in a delicate course so as to minimize damage to clothes and improve a spin-drying efficiency in a middle spin-drying operation after a washing operation and in a final spin-drying operation after a final rinsing operation.

First, when a user selects the delicate course under the condition that clothes (laundry) requiring delicate washing, such as a wool or silk fabric, a shirt, a rayon fabric, and a women's top, are put into the rotary drum 12 (S200), operation data, selected by the user, are inputted to the control unit 140 through the signal input unit 100.

Thereafter, the control unit 140 performs washing and rinsing operations proper to the delicate course according to the operation data inputted from the signal input unit 100. Here, the control unit 140 first determines whether or not the washing machine is turned on (S202).

When it is determined that the washing machine is turned on, the control unit 140 sets a water amount for the washing and rinsing operations and a rinsing frequency according to a load (the weight or amount of the clothes) put into the rotary drum 12, and then turns on the water supply valve 24 so that water is supplied to the detergent supply device 18 through the water supply pipe 22. Then, the water (washing water) supplied to the detergent supply device 18 contains a detergent in the detergent supply device 18, and the obtained detergent water (water+detergent) is supplied to the tub 11 through the connection pipe 26.

When the detergent water is supplied to the tub 11, the control unit 140 operates the motor 13 at a predetermined motor RPM and motor operation factor, and thus performs a washing operation, in which the clothes are well mixed with the detergent water by the rotation of the rotary drum 12 and are washed by the friction with the rotary drum 12 and the falling force of the clothes (S204).

After the washing operation, the control unit 140 operates the drain pump 32 so as to drain the detergent water in the tub 11 through the drain pipe 31 (S206). Then, the control unit 140 performs a middle spin-drying operation at a predetermined RPM (approximately 250˜400 RPM) and operates the fan 41 of the drying device 40 so as to supply cold air from the drying duct 42 to the inside of the rotary drum 12 (S208).

In the case of the delicate clothes, which cannot be spin-dried, the middle spin-drying operation after the washing operation is not skipped, the RPM of the motor 13 in the spin-drying operation is maximally reduced, and cold air is supplied to the rotary drum 12. Then, it is possible to minimize damage to the clothes and increase a spin-drying effect. Further, it is possible to prevent the deterioration of a rinsing efficiency due to the low spin-drying degree.

As described above, the reason why the RPM of the motor 13 in the middle spin-drying operation in the delicate course is reduced to approximately 250˜400 RPM, being lower than the RPM of the motor 13 in the middle spin-drying operation in the standard course, i.e., approximately 600˜1,000 RPM, is that damage to the clothes is minimized and cold air is supplied to the rotary drum 12 so as to increase the spin-drying effect.

When the middle spin-drying operation is completed after the washing operation, the control unit 140 turns on the water supply valve 24 so as to perform a rinsing operation, and then water (rinsing water) is supplied to the inside of the tub 11.

When the water (rinsing water) is supplied to the inside of the tub 11, the control unit 140 operates the motor 13 at a predetermined motor RPM and motor operation factor, and thus performs the rinsing operation (S210).

After the rinsing operation, the control unit 140 operates the drain pump 32 so as to drain the detergent water in the tub 11 through the drain pipe 31 (S212). Then, the control unit 140 determines whether or not the rinsing operation is a final rinsing operation (S214).

The frequency of the rinsing operation is set to approximately 1˜5 times according to the load or the data regarding the addition of rinsing, which is selected by a user.

As a result of the determination of the step S214, when it is determined that the rinsing operation is not the final rinsing operation, a method of an exemplary embodiment is fed back to the step S210, and the rinsing operation is repeated at the set frequency. On the other hand, when it is determined that the rinsing operation is the final rinsing operation, the control unit 140 performs a final spin-drying operation at the predetermined RPM (approximately 250˜400 RPM) identically with the middle spin-drying operation after the washing operation, and operates the fan 41 of the drying device 40 so as to supply cold air from the drying duct 42 to the inside of the rotary drum 12 (S216).

In the case of the delicate clothes, which restrictively employs the final spin-drying operation due to damage to the clothes, the final spin-drying operation is not skipped, the RPM of the motor 13 in the spin-drying operation is maximally reduced, and cold air is supplied to the clothes. Then, it is possible to minimize damage to the clothes and increase a spin-drying effect. Further, it is possible to prevent the deterioration of a spin-drying efficiency due to the low spin-drying degree.

As described above, the reason why the RPM of the motor 13 in the final spin-drying operation in the delicate course is reduced to approximately 250˜400 RPM, being lower than the RPM of the motor 13 in the final spin-drying operation in the standard course, i.e., approximately 1,100˜1,200 RPM, is that damage to the clothes is minimized and cold air is supplied to the rotary drum 12 so as to increase the spin-drying effect (the shortening of a drying time by 25% compared with a conventional method: 6 minutes→4 minutes 30 seconds).

As apparent from the above description, an exemplary embodiment provides a washing machine having a drying device, which performs a spin-drying operation at a maximally low RPM and supplies cold air to clothes in a delicate course so as to minimize damage to the clothes and improve rinsing and spin-drying efficiencies, and another exemplary embodiment provides a method for controlling spin-drying of the washing machine.

Further, since the supply of the cold air does not require high energy consumption and is applied to any kind of clothes, a washing machine of an exemplary embodiment has a high utility.

Although a few exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these exemplary embodiments, the scope of which is defined in the claims and their equivalents. 

1. A method for controlling spin-drying of a washing machine, which has a rotary drum for containing laundry, a motor for rotating the rotary drum, and a fan for circulating air, comprising: determining whether a delicate course is selected; performing low-speed spin-drying in which the rotary drum is rotated at a low speed by operating the motor at a low revolutions per minute (RPM), when the delicate course is selected; and supplying cold air to the inside of the rotary drum by operating the fan together with the low-speed spin-drying.
 2. The method according to claim 1, wherein the low RPM of the motor is at least 250 RPM.
 3. The method according to claim 2, wherein the low RPM of the motor is in the range of 250˜400 RPM.
 4. The method according to claim 1, wherein the low-speed spin-drying is performed such that the motor is operated at the low RPM in a middle spin-drying operation after a washing operation.
 5. The method according to claim 1, wherein the low-speed spin-drying is performed such that the motor is operated at the low RPM in a final spin-drying operation.
 6. The method according to claim 1, wherein the cold air is supplied to the inside of the rotary drum such that the fan is operated during operation of the motor at the low RPM so as to supply the cold air generated from the fan to the inside of the rotary drum rotating at the low speed.
 7. A washing machine comprising: a rotary drum to contain laundry; a motor to rotate the rotary drum; a fan to circulate air; and a control unit to control spin-drying in a delicate course by operating the motor at a low revolutions per minute (RPM) so as to perform low-speed spin-drying in which the rotary drum is rotated at a low speed, and to operate the fan together with the low-speed spin-drying so as to supply cold air to the inside of the rotary drum.
 8. The washing machine according to claim 7, wherein the control unit controls the motor such that the low-speed spin-drying is performed in a middle spin-drying operation after a washing operation.
 9. The washing machine according to claim 7, wherein the control unit controls the motor such that the low-speed spin-drying is performed in a final spin-drying operation.
 10. The washing machine according to claim 7, wherein the low RPM of the motor is at least 250 RPM.
 11. The washing machine according to claim 10, wherein the low RPM of the motor is in the range of 250˜400 RPM.
 12. The washing machine according to claim 7, further comprising a duct for guiding the route of the air circulated by the fan, wherein the fan is installed in the duct.
 13. The method of claim 1, further comprising: performing washing and rinsing operations; and skipping a middle spin-drying operation after washing and rinsing operations are completed to perform the low-speed spin drying.
 14. The washing machine according to claim 7, wherein the control unit controls the washing machine to perform washing and rinsing operations and to skip a middle spin-drying operation after washing and rinsing operations are completed in order to perform the low-speed spin drying. 